The Deep Gnomes (Svirfneblin) are a subrace of gnomes from the Underdark. They are quick and perceptive, yet suspicious and reclusive to an extreme. Svirfneblin have gnarled physiques, brown or gray skin, gray eyes, and gray hair (although males are often bald). They tend to be sullen, withdrawn, and suspicious to a fault.

The deep gnomes may be the among the stealthiest and most elusive of races. Centuries upon centuries of surviving the deadly perils of the Underdark have bred in this race an amazing gift for avoiding attention. In their cavern homes they are nearly undetectable with magic. Even in the strange and threatening (to them) surface world, the deep gnomes' natural stealth makes them difficult to spot or catch.

[Source: Forgotten Realms Campaign Setting by Greenwood, Reynolds, Williams, and Heinsoo, published by Wizards of the Coast, page 11-13.]